Median perturbation theory for fluids with delta model potential

The use of the angular median potential as a temperature-independent spherical reference system in thermodynamic perturbation is tested for its prediction of the internal energies of delta-model potential fluids. The results from the median theory, as compared to the simulation results, indicate that the median potential provides a satisfatory reference system only for slightly prolate molecules. This bears a close parallel to the situation for the diatomic Lennard-Jones fluids where the median is excellent for molecules with small elongation. (Author)